This invention relates to a cylindrical lockset and particularly relates to a cylindrical lockset which includes a spring cassette actuated directly by an operator, such as a lever, associated with the lockset.
In some cylindrical locksets in use today, a spring cassette is used to return the lockset operator, such as a lever, to its home or non-operated position when it is released. Typically, the cassette is approximately the size of the rose of the lockset and a torsion spring contained within the cassette is only slightly smaller. The spring is formed with an inner free end from which overlapping convolutions of successively larger diameters is formed. The spring is further formed with an outer free end at the terminus of the outer most convolution thereof.
The cassette includes a dish-like receptor for the spring and a cover for containing the spring. An arbor is located centrally within the cassette for rotation independently thereof and is keyed to a rollback sleeve for rotation therewith. The inner end of the spring is attached to the arbor and the outer end of the spring is attached to the receptor which is fixedly mounted. An operator, such as a lever, is attached to the rollback sleeve and, when operated, rotates the sleeve. Through the keying structure of the sleeve, the arbor is rotated to tension the spring which provides the force to return the operator to its home position upon release thereof.
Spring cassettes of this type operate exceptionally well and are of sufficient bulk to respond to heavy duty demands. Even so, such cassettes and related facilities are relatively large and require specialized manufacturing and handling of several components which is directly related to cost. Further, the application of the tensioning force as applied to the spring by operation of the lever must be coupled through several components including the sleeve, the keying structure and the arbor.
Thus, there is a need for a lighter duty spring cassette with a more direct facility for tensioning the spring by operation of the lever.
Also, a door, on which a currently available cylindrical lockset is to be mounted, is prepared for assembly of the lockset therewith by forming various through-holes. For example, a central hole is formed through the door for receipt of the chassis. A pair of smaller holes are formed through the door adjacent the central hole for receipt of screws therethrough which are passed through holes in an inside liner and into internally threaded posts in an outside liner to pull together and hold the liners with the door. Typically, the pair of holes are formed in a diagonal pattern with an imaginary line passing diametrically across the central hole and through the pair of holes. When the hand of the door is to be changed, the door is prepared with the holes located adjacent the opposite side edge of the door with the outside of the door remaining as the outside. However, the pair of smaller holes in the new preparation are shifted by ninety degrees from the location of the previous pair of smaller holes. The inside liner which was used with the first above-described arrangement of holes has two holes formed therethrough to facilitate alignment of the liner holes with the first pair of smaller holes. Thus, this inside liner does not have holes which will align with the second pair of smaller holes and, therefore, is not functional or useful with the second set of holes which were prepared for a change of hand of the door. In this instance, the inside liner is dedicated for use with the first set of prepared door holes and another inside liner must be made which is dedicated for use with the second set of prepared holes.
Thus, there is a need for facility to allow for the use of a single inside liner regardless of the hand orientation of the door.
Typically, cylindrical locksets are assembled with doors of different thicknesses. For example, the thickness dimensions of three selected doors are one and three-eighths inches, one and three-quarters inches and two inches. Other thicknesses may be used.
In any event, an outside liner must be spaced from an associated inside liner on opposite sides of a chassis to define the door thickness. With current arrangements, the outside liner is mounted in assembly with the chassis and can be adjusted by an installer who uses a measuring scale to locate the outside liner with respect to a housing of the chassis. While this technique accomplishes the desired end result, it requires tedious manipulation of the inside liner by the installer while holding the measuring scale.
Thus, there is a need for facility to allow accurate location of the outside liner with respect to the chassis housing, preferably at the factory but also with allowance for on-site adjustment by the installer.